1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device and more particularly to an LCD device being capable of fixing an optical sheet.
2. Discussion of the Related Art
As information technology and mobile communication technology have been developed, a display device being capable of displaying a visual image has also been developed. The display device is classified into a projection type and a direct type. The direct type display device is also classified into a self-emission type and non-emission type. For example, the liquid crystal display device is classified into the non-emission type display device.
Since the LCD device does not include a light source therein, an additional light source is required. For example, a backlight unit including a lamp is disposed under a liquid crystal panel to provide light onto the liquid crystal panel. The LCD device can display images using the light from the backlight unit.
Generally, the backlight unit is classified into a side type and a direct type depending on a position of the light source. In the side type backlight unit, the light source is positioned at a side of the backlight unit. The light from the light source in the side type backlight unit is refracted by a light guide plate to proceed to the liquid crystal panel. On the other hand, in the direct type backlight unit, the light source is positioned at a center of the backlight unit such that the light from the light source is directly provided to the liquid crystal panel.
FIG. 1 is a cross-sectional view of the related art LCD. In FIG. 1, the LCD includes a liquid crystal panel 10, a backlight unit 20, a main frame 30, a top frame 40 and a bottom frame 50.
The liquid crystal panel 10 is a major element for displaying images. The liquid crystal panel 10 includes a first substrate 12, a second substrate 14 and a liquid crystal layer (not shown). The first and second substrates 12 and 14 face each other, and the liquid crystal layer is interposed therebetween.
The backlight unit 20 is disposed under the liquid crystal panel 10. The backlight unit 20 includes a lamp 24 as a light source, a lamp guide 25 for guiding the lamp 24, a reflective sheet 22, a light guide plate 26 and an optical sheet 28. The lamp 24 is arranged along at least one side of the main frame 30. The reflective sheet 22 is disposed on the bottom frame 50 and has a color of white or silver. The light guide plate 26 is disposed on the reflective sheet 22, and the optical sheet 28 is disposed on or over the light guide plate 26.
The liquid crystal display panel 10 and the backlight unit 20 are combined using the main frame 30 that can prevent movement of the liquid crystal panel 10 and the backlight unit 20. The top frame 40 cover edges of the liquid crystal panel 10 and sides of the main frame 30, so the top frame 40 can support and protect of the edges of the liquid crystal panel 10 and sides of the main frame 30. The bottom frame 50 covers back edges of the main frame 30, so the bottom frame 50 is combined with the main frame 30 and the top frame 40 for modulation.
The optical sheet 28 is disposed on the light guide plate a special fixing member such that there is movement of the optical sheet 28. As a result, the optical sheet 28 may go out of a desired position. In this case, there are damages on the optical sheet 28 when the main frame 30 and the bottom frame 50 are modulated. Since the LCD display can not display an uniform image because of the damaged optical sheet 28, a production yield is decreased.